Cable for electric-current-distributing systems.



P. V. HU NTER.

CABLE FOR ELECTRIC CURRENT DISTRIBUTING SYSTEMS.

APPLICATION FILED FEB. 14, 1912. RENEWED SEPT. 5, 1913.

v 1,088,902. Patented Mar. 3, 1914.

which the followin is-a specification.

.tically proportionate to t PHILIP VASSAR HUN TIER, 0F NEWCASTLE-UPON-TYNE, ENGLAND.

CABLE FOR ELEGTRIC-CURRENT-DISTRIBUTING SYSTEMS.

Specification of Letters Patent.

Patented Mar. 3, 1914.

Application filed February 14, 1912, Serial No. 677,461. Renewed September 5, 1913. Serial No. 788,325.

To al l whom it may concern:

' Be: it known that I, PHILIP VAssAn' Hniq'rnn, a'subject {of-the King of -Great Britain and Ireland, residing at -Heaton, Newcastle-upon-Tyne, in the county of Northumberland, England, have invented Improvements in or Relating to Cables for Electric-Chrrent-Distributing. Systems, of

This inventipn re ates to cables for electric systems of the kind in which current for. power or lighting purposes is distributed". with the aid of leads connected infp'arallel, as for example isnecessary to secure pro--' tection in accordance with the arrangements. describedin the specification'of my application for Letters Patent Serial No". 641,511 filed "Jul 31st, .1911. i

- The o of the; present invention is; to provide acheap. construction "of cable for, can'ying-leadsas aforesaid. For this pun-*- pose, the cable comprises a pair- 0f leads of similarjmetal adapted to be usedin parallel sothat no appreciable difference of )ot"ent i al" normally exists between them and'separated from-each'other by insulating material that"; eonsequentlyneed not be thick norlfloffa high ade or in other words is of abnormally low insulation value. In this way," in a d-istrib-l utin'gsystem, whereheretofore the l ds i were carried in Separate cables, the initial -'outlay Tis'decreased since the 'cost of distributing systems embod ing cables is 'p'ra'c he number'of cables employed and'not to their capacity;

Figures 1, 2 and 3 of the accompanying; drawings-are sections of cables accordin -to the invention. 1 Figs. 4 and 5 are views il ustrating different ways of arranging the cores of cables according to the invention. Fig. 1 illustrates acable for a three phase system having a pair of leads a, b foreacli phase, the two leads of each pairbei'ng "ofj similar electrical potential gand arranged concentrically so as to be mutually inductive" with a non-conducting separator- 9 between them and forming one core of the cable. As there is normally no difference of potential between the leads (1,6 the non-conducting.

separator g need have only sufiicient insulatmg properties to withstand the momentary di erence of pressure which would exist should a leakage occurfrom a or b to earth or another feeder. The two leads are extremely close together and have a maximum mutual induction. If it is desired to arrange the feeders so that the leads have equal -,current between the two leads by unequal inductive effects on the two leads of currents in adjacent feeders or earth.

In an alternative construction, shown in' Fig. 2,,the two leads a, b of each pair of leads are'arranged side by side, so as to be mutually; inductive, with a non-conducting separator g betweenthem, each lead being, it may be, of 'semi-circulars ection as shown. The twoleads may, as indicated in 'Fig. 5, be arranged spirally around each other to prevent'unequal division of currents in the two leads due to the'effect of currents'inadjacent feeders or earth.- 1

In a further.- alternative construction, shown in Fig. 3, two leads a, b o'fi solid semicircular eross section, as in Fig. 2, are employed, and two pairs of leads a b of approximately hollow semi-circular cross-sec- 'tional shape such pairs being assembled to occupy concentrically arranged circular spaces in the cable'at the center of which 'are'arrangedthe two leadsva, b. u v

The several duplex cores at different potential in the same cable are suitably insulated from each other but as the two leads of'eachcore are of equal potential the separatinl'g material y between them need not be of a ighly insulating character, thus enabling the cables to be cheaply constructed.

Where-the insulation value ofthe insulating material between the leads in the cables is spoken of as being abnormally low, is meant insulation value .which would be deemedabnormally low in cables used for ordinary purposes ofeiectric current distribiltingsystems as employed at this date; To further assist in ascertaining the limi tations imposed upon the present invention I may state that I am aware that it has been ,proposedtoseparate stranded cores at difrent potentials by insulation material that is mec anically weak, with the intention, when an accident occurs of causing its destruction rather than destruction of the outer insulation, and that it has been proposed to combine with a single current carrying lead a lead of dissimilar metal not intended to carry current but to act to reduee the objectionable efiects of capacity in telegraphy and telephony by rendering the conductor self inductive, the two leads being preferably separated by insulating material though not necessarily so.

What I claim is 1. In an electric distribution system, a cable comprising a pair of leads, insulating material of abnormally low insulation value separating sueh leads thereby enabling the leads to be used in parallel with no appreciable dillerence of potential between them, and insulating material surrounding said pair of leads, collectively, of a much greater insulating value than the material separating the leads, substantially as described.

2. In an electric distribution system, a cable comprising a pair of leads, material of abnormally'low insulating value separating such leads thereby enabling the leads to be used in parallel with no appreciable difference of potential between them and in such close proximity one to another that the re action of one upon the other by mutual induction with disturbance in the proportion of currents carried is rendered very pronounced, and material. surrounding said pair of leads, that is collectively, of a much greater insulation value than the material separating the leads, substantially as described.

3. In an electric distribution system, a cable comprising a pair of leads, insulating material of abnormally lowinsulation value separating such leads, thereby enabling the leads to be used in parallel with no appreciable difference of potential between them, and insulating material surrounding such pair of leads, collectively, of a much greater insulation value than the material separating the leads, the leads being arranged to occupy different positions at intervals throughout the length of the cable to prevent alteration to the division of current between the two leads by unequal inductive efi'ects due to extraneous currents.

4. In an electric distribution system, a cable comprising a pair of leads, material of an abnormally low insulation value separating such leads thereby enabling the leads to be used in parallel With no appreciable difference of potential between them and in such close proximity one to another that the reaction of one upon the other by mutual induction with disturbance in the proportion of currents carried by them is rendered very pronounced, and insulating material surrounding said pair of leads, collectively, of a much greater insulation value than the material separating the leads, the leads being each divided into an even number of sections of equal lengths and each section of each lead being connected to a non-corresponding section of the other lead.

5. In an electric current distribution system, a cable having cores separated one from another by insulation commensurate with the diile'renee of potential required therebetween, each core comprising divided leads between which there is normally no difference of potential and separated by insulating material commensurate with the momentary difference of pressure which may exist between the leads should leakage occur.

6. In any electric current distribution system, a cable comprising a pair of leads of similar metal adapted to be used in parallel and so that no appreciable difference of-potential exists between them and insulating material of abnormally low insulation value but mechanically strong, separating one lead from the other, substantially as set forth.

Signed at Newcastle-on-Tyne, England, this twenty ninth day of January, 1912.

PHILIP VASSAR HUNTER.

Witnesses H. NIXON, FRED H. DUKE. 

